Adult bikes come in several different wheel sizes, depending on the type of bike. Road and hybrid bikes generally have 700c wheels; mountain, comfort and cruiser bikes can have 26", 27.5" or 29" wheels. However, adult bike fit is more often determined by the frame size:

If a bike only comes in one size, it will usually fit most adults 5'3" or taller.

If a bike comes in multiple sizes, refer to the chart and links below to determine the best fit for you.